Red Hat Enterprise Linux 6.4 and onward include Microsoft's Linux Integration Services, a set of drivers that enable synthetic device support in supported virtualized operating systems. Further details about the drivers provided are available from http://technet.microsoft.com/en-us/library/dn531030.aspx
Note that the built-in Red Hat Enterprise Linux Integration Service drivers for Hyper-V are sufficient for Red Hat Enterprise Linux guests to run using the high performance synthetic devices on Hyper-V hosts. These built-in drivers are certified by Red Hat for this use, and certified configurations can be viewed on the Red Hat Customer Portal
Therefore, it is not necessary to download and install Linux Integration Services (LIS) packages, and doing so may limit your Red Hat support, as described in the related Knowledgebase article
The following enhancements have been made to allow for easier deployment and management of Red Hat Enterprise Linux guest virtual machines:
Upgraded VMBUS protocols - VMBUS protocols have been upgraded to Windows 8 level. As part of this work, now VMBUS interrupts can be processed on all available virtual CPUs in the guest. Furthermore, the signaling protocol between the Red Hat Enterprise Linux guest virtual machine and the Windows host physical machine has been optimized.
Synthetic frame buffer driver - Provides enhanced graphics performance and superior resolution for Red Hat Enterprise Linux desktop users.
Live Virtual Machine Backup support - Provisions uninterrupted backup support for live Red Hat Enterprise Linux guest virtual machines.
Dynamic expansion of fixed size Linux VHDXs - Allows expansion of live mounted fixed size Red Hat Enterprise Linux VHDXs.
Boot using UEFI - Allows virtual machines to boot using Unified Extensible Firmware Interface (UEFI) on a Hyper-V 2012 R2 host.